People who leave prison with HIV and a substance use disorder (SUD) have the dual risks of relapse 14,6,50 and poor antiretroviral therapy (ART) medication adherence.4 These risks are exacerbated by the stress associated with community re-entry from prison.6, 67 The goal of the proposed research training grant is to test a hatha yoga intervention's (HYI) impact on the health outcomes of 72 people recently released from prison with HIV and SUD. Participants will be randomized to either treatment as usual (TAU) comprised of case management services, or HYI comprised of 12-weekly 90-minute hatha yoga classes in addition to case management services. The proposed mixed methods study will examine 1) the effects of HYI on stress, substance use, ART adherence, viral load and coping self-efficacy as compared with TAU; and 2) participants' perspectives regarding their stress responses and how these stress responses are affected by treatment assignment to HYI or TAU, as assessed through 30 semi-structured qualitative interviews. Findings will inform the development of interventions for people with HIV and SUD experiencing re-entry to the community from prison. The proposed randomized controlled trial will be accomplished through extensive quantitative and qualitative training provided by classwork and research seminars at the University of Pennsylvania, and mentorship from sponsor Dr. Jim McKay and co-sponsor Dr. Malitta Engstrom.